Histologic findings in an adult Eurasian Eagle Owl (Bubo bubo) admitted for rehabilitation in the Republic of Korea. H&E (left) and acid-fast (right, counterstain with methyl green) staining. (a) Skin on the left carpal area. Acanthosis, caseous necrosis, and pseudomembrane (asterisks) in the epidermis. Acid-fast stain positive cells (red arrows) are seen in the epidermis. (b) Solid neoplasm on the left carpal area. Caseous necrosis (asterisk) and acid-fast stain positive cells (red arrows). Insert: higher magnification. Granulomas with central caseous necrosis (asterisks), peripheral multinucleated giant cells (black arrows), and acid-fast stain positive cells (red arrows) in the (c) heart and (d) lung; insets show higher magnification. (e) Acid-fast positive giant cell (black arrow). Bar=20 µm.